1. Field of the Invention
The invention relates to a metering device for removing a medium from a pressurized medium container, wherein the medium is provided in particular for the maintenance of medical instruments.
2. Related Technology
In medical technology, the exact metering of media is essential to be able to successfully carry out a treatment or another work procedure. This also applies, among other things, to the metering of media for disinfection, cleaning and maintenance of medical appliances, particularly when these are in direct contact with a patient. Account must be taken of many kinds of interactions which, in some circumstances, can even pose a danger to the life of the person being treated. For example, incorrect metering of a medium used for the cleaning and maintenance of medical appliances could result in an inadequate disinfection or in dilution or neutralization of a treatment agent.
Moreover, in the case where care agents are being metered, it is also necessary to bear in mind that a reliable function of the medical appliance has to be ensured over a long period of time, with minimization of the work involved in servicing. All of these peripheral conditions and requirements result in the need for small quantities of a medium to be able to be metered in a precise manner and discharged exactly at a defined time.
For this purpose, metering containers are known which have a hollow space whose volume is dimensioned such that it can take up exactly the quantity of medium that is to be metered. However, when filling with gases, it is necessary that, in addition to the temperature of the gas, the filling pressure of this hollow space must also be kept within narrow tolerances.
If it is intended to couple a closed and pressurized medium container to the metering container, then the problem additionally arises that the pressure at which the medium reaches the metering container decreases with the number of cycles of removal of medium from the medium container. Particularly with compressible media, the metered quantity of medium can be kept constant only with difficulty.